1. Field of the Invention
This invention relates to reels for harvesting machines, such as mower/conditioners, combines, hay balers, forage harvesters, hay rakes and the like and, more particularly, to such reels including tines and means for permitting the tines to deflect and ride over substantially immovable objects encountered by the tines during operation of the harvesting machine.
2. Description of the Prior Art
Hay harvesting machines, such as self-propelled and tractor-pulled mower/conditioners, typically include a reel rotatably mounted on a header for sweeping through a standing crop and assisting and placing the crop in an upright position for cutting by a reciprocating sickle or other cutting means located below the reel. This type reel usually includes a plurality of circumferentially spaced, radially extending arms supported on a rotatable shaft driven by a suitable power source during the harvesting operation. These support arms carry a plurality of circumferentially spaced bat tubes or bat tube/bat units extending generally parallel to the rotational axis of the reel. Each bat tube or bat tube/bat unit carries a row of axially spaced tines which sweep through the crop to further assist in placing them in a proper orientation for cutting and then sweeping and lifting the severed crop material upwardly and rearwardly into an auger or conditioning rolls at an angular orientation which promotes a clean release of the severed crop material.
The bat tubes or the bat tube/bat units are rotatably mounted on the support arms and one end of each includes a cam follower which rides in a cam track extending 360.degree. around the rotational axis of the reel. Portions of the cam track are located at different radial distances from the rotational axis of the reel so that, during rotation of the reel, the bat tubes or bat tube/bat units are rotated back and forth about their rotational axes to position the tines at the most advantageous angular orientation for each phase of the sweeping action.
Reels including similar bat tubes or bat tube/bat units and tines are used in other harvesting machines, such as pick up reels for combines, pick up attachments for hay balers and forage harvesters and hay rakes.
The tines for hay harvesting machines are faced with a problem not as commonly encountered by tines on pick up reels for combines and reels for other types of harvesting machines. The tines on hay harvesting machines often encounter plugs of wet hay or other substantially immovable obstructions which do not give. Consequently, to minimize the likelihood of permanent damage to the tines, they must deflect or give to some degree so they can ride over the plug or other obstruction. To provide this capability, the tines for hay harvesting machines typically are in the form of steel spiral springs which are slipped over and fastened to a bat tube, for example, as illustrated in FIG. 3 of U.S. Nickel et al. U.S. Pat. No. 5,007,235.
When such tines break, the broken off portion can fall into and damage the sickle and other parts of the machine and end up in livestock feed. To replace a broken tine, a bat tube must be removed, all tines between one end of the bat tube and the broken one must be unfastened and slipped off the bat tube before the broken tine can be removed and then all these tines slipped back on the bat tube and fastened after the broken tine has been replaced. For pick up reels and other type reels for harvesting machines where the tines are less apt to encounter similar obstructions, these and other shortcomings associated with metal spring tines have been minimized by using tines made from a synthetic thermoplastic or thermosetting material. However, tines made from such plastic materials cannot be deflected upon engaging a plug of wet hay or other obstruction and then return to their previous orientation. Instead, they tend to quickly become permanently deformed and ineffective for their intended purpose. Spring loading each tine would be quite difficult and costly. Accordingly, a simple means for taking advantage of tines made from a plastic material and yet minimizing permanent deformation of such tines during use is highly desirable.
Representative prior art patents disclosing reels for hay harvesting machines includes Nickel et al. U.S. Pat. No. 5,007,235. Representative prior art patents disclosing plastic tines include Hubbard U.S. Pat. No. 3,613,346, Heal et al. U.S. Pat. No. 3,796,030, Gessel et al. U.S. Pat. No. 4,520,620 and Jasper et al. U.S. Pat. No. 4,882,899. Representative prior art patents disclosing either metal spring tines or spring load fingers for reels include Rasmussen U.S. Pat. No. 3,302,378, Gradwohl U.S. Pat. No. 3,771,299 and Kirby U.S. Pat. No. 4,255,921.